2. THE SKELETAL SYSTEM The Appendicular Skeleton 2 pairs of limbs and 2 girdles Pectoral (shoulder) girdle attaches upper limbs Pelvic (hip) girdle secures lower limbs 3-Segmented limbs Upper = arm Arm Forearm Hand Lower = leg Thigh Leg Foot
3. PectoralGirdle(Shoulder Girdle) Clavicle anterior: collar bone Sternal end attaches to the manubrium medially Acromial end articulates with the scapula laterally Scapula posterior: shoulder blade
4. Scapulae: triangular, paired, but dontconnect in back (adds thoracic flexibility)
5. Scapula Glenoid cavity articulates with the humerus Acromium articulates with clavicle Coracoid process projects anteriorly
6. Upper extremity Arm or Brachium = upper arm Between shoulder and elbow (humerus) Forearm or Antebrachium Radius & ulna Hand includes: Wrist (carpus) Palm (metacarpus) Fingers (phalanges)
7. Arm Humerus is the only bone Head of humerus fits into glenoid cavity of scapula Distal & medially, trochlea articulates with the ulna Distal & laterally capitulum articulates with the radius Medial & lateral epicondyles
8. Righthumerus,anterior view
9. Righthumerus,posterior view
10. Radius is thinner proximally, like a spool Forearm of thread, and wide distally; ulna is slightly longer and looks like a monkey wrench (supposedly!) 2 bones: articulate with each other proximally and distally Interosseous membrane between them Ulna Olecranon hinges with the humerus forming elbow Styloid process distally Radius Contributes to wrist joint Styloid process anchors a ligament to wrist (thumb side)
11. Right forearm bones,anterior view
12. Right forearm bones,posterior view
13. In the anatomical position, the radius is Left forearm lateral (thumb side); with pronation the palm faces posteriorly and the bones cross prone Anatomical Prone: body lying face down position Suppine: body lying face up (you can remember prone if you think about how you would fall forward onto your face if you passed out)pronation moves the forearm into theprone position and supination movesit back to the anatomical position
14. Proximal and distal joints of the forearm proximal ulna
15. Hand Proximal is wrist 8 carpal bones Palm of hand - 5 metacarpals Fingers (or digits) consist of miniature long bones called phalanges: thumb (pollex) has 2; fingers have 3: proximal, middle, distal Right hand, 2 views:
16. Pelvic Girdle(Hip Girdle) Strongly attached to axial skeleton (sacrum) Deep sockets More stable than pectoral (shoulder) girdle Less freedom of movement Made up of the paired hip bones Bony pelvis is basin-like structure: hip bones plus the axial sacrum and coccyx
17. Hip bone (os coxae): 3 separate bones in childhood which fuse Ilium Ischium Pubis
18. Ilium ilium Iliac crest Anterior superior iliac spine Greater sciatic notch Forms part of acetabulum (hip socket) ilium which receives ball-shaped head of femur
19. Ischium Body Ramus Ischial spine ischium Ischial tuberosity Part of socket ischium
20. Pubis Joins medially in pubic symphysis pubis Forms obturator foramen (large hole) with ischium Part of socket pubis
21. Hip bones with labels
22. False (greater) and true (lesser) pelvisLigaments
23. Pelvis and childbearing Male/female differences Large & heavy vs light & delicate Heart shaped pelvic inlet vs oval Narrow deep true pelvis vs wide & shallow Narrow outlet vs wide Less than 90 degree pubic arch vs more than 90 degree Birth canal changes shape as baby descends: head turns Higher:pelvic inlet (brim) - side to side largest Lower: pelvic outlet - largest in AP direction
25. Thigh Femur is largest, longest and strongest bone in the body Head fits in socket (acetabulum) of pelvis Neck is weakest Greater trochanter Distal: lateral & medial condyles and epicondyles Patella: sesmoid bone
26. Right femur,anterior view
27. Right femur,posterior view
28. Leg Tibia: shin bone Medial and lateral condyles Tibial tuberosity Distal medial malleolus (medial ankle) Fibula Distal lateral malleolus (lateral ankle) Interosseous membrane
29. Right lowerleg, anterior view
30. Foot Tarsus: 7 tarsal bones Talus: articulates with tibia and fibula anteriorly and calcaneus posteriorly Calcaneus: heel bone Smaller cuboid, navicular, and 3 cunieforms (medial, intermediate and lateral) 5 metatarsals 14 phalanges Great toe is hallux
